package com.hmdp.service.impl;


import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.util.*;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {


    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);
        //缓存击穿
//        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.SECONDS);
        if(shop==null){
            return Result.fail("店铺不存在");
        }
        return Result.ok(shop);
    }
    //互斥锁 防止缓存击穿
//    public Shop queryWithMutex(Long id){
//        String key = CACHE_SHOP_KEY + id;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        if(StrUtil.isNotBlank(shopJson)){
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//        }
//        if (shopJson!=null){
//            return null;
//        }
//        //开始实现缓存重建
//        //获取互斥锁
//        String lockKey = LOCK_SHOP_KEY + id;
//        Shop shop = null;
//        try {
//            boolean isLock = tryLock(lockKey);
//            if(!isLock){
//                //失败，休眠重试
//                Thread.sleep(50);
//                return queryWithMutex(id);
//            }
//
//            shop = getById(id);
//
//            if (shop==null) {
//                stringRedisTemplate.opsForValue().set(key,"",
//                        RedisConstants.CACHE_NULL_TTL,TimeUnit.MINUTES);
//                return null;
//            }
//            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),
//                    RedisConstants.CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        } catch (InterruptedException e) {
//            throw new RuntimeException(e);
//        } finally {
//            unlock(lockKey);
//        }
//        //释放锁
//        return shop;
//    }
//    private boolean tryLock(String key){
//        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
//        return BooleanUtil.isTrue(flag);
//    }
//    private void unlock(String key) {
//        stringRedisTemplate.delete(key);
//    }
//
//    public void saveShop(Long id,Long expireSeconds){
//        Shop shop = getById(id);
//        RedisData redisData = new RedisData();
//        redisData.setData(shop);
//        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id
//                ,JSONUtil.toJsonStr(redisData));
//    }
//    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
//    public Shop queryWithLogicalExpire( Long id ) {
//        String key = CACHE_SHOP_KEY + id;
//        // 1.从redis查询商铺缓存
//        String json = stringRedisTemplate.opsForValue().get(key);
//        // 2.判断是否存在
//        if (StrUtil.isBlank(json)) {
//            // 3.存在，直接返回
//            return null;
//        }
//        // 4.命中，需要先把json反序列化为对象
//        RedisData redisData = JSONUtil.toBean(json, RedisData.class);
//        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
//        LocalDateTime expireTime = redisData.getExpireTime();
//        // 5.判断是否过期
//        if(expireTime.isAfter(LocalDateTime.now())) {
//            // 5.1.未过期，直接返回店铺信息
//            return shop;
//        }
//        // 5.2.已过期，需要缓存重建
//        // 6.缓存重建
//        // 6.1.获取互斥锁
//        String lockKey = LOCK_SHOP_KEY + id;
//        boolean isLock = tryLock(lockKey);
//        // 6.2.判断是否获取锁成功
//        if (isLock){
//            CACHE_REBUILD_EXECUTOR.submit( ()->{
//
//                try{
//                    //重建缓存
//                    this.saveShop(id,20L);
//                }catch (Exception e){
//                    throw new RuntimeException(e);
//                }finally {
//                    unlock(lockKey);
//                }
//            });
//        }
//        // 6.4.返回过期的商铺信息
//        return shop;
//    }
    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id==null){
            return Result.fail("店铺id不能为空");
        }
        updateById(shop);
        stringRedisTemplate.delete(CACHE_SHOP_KEY + shop.getId());
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //判断是否需要根据坐标查询
        if(x==null||y==null){
            Page<Shop> page = query().eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            return Result.ok(page.getRecords());
        }
        // 1.计算分页参数
        int from = (current-1)*SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current*SystemConstants.DEFAULT_PAGE_SIZE;
        // 2.查询redis
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo() // geosearch key bylonlat
                .search(key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoRadiusCommandArgs.newGeoRadiusArgs().includeDistance().limit(end)
                );
        if (results==null){
            return Result.ok(Collections.emptyList());
        }
        // 3.解析出id
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size()<=from){
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());
        //从分页的from开始截取到结束
        list.stream().skip(from).forEach(result->{
            // 获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            // 获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        // 4.根据id查询
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Shop shop : shops) {
            Distance distance = distanceMap.get(shop.getId().toString());
            shop.setDistance(distance.getValue());
        }
        // 5.返回
        return Result.ok(shops);
    }
}
